Hensley departs from his Donald Robak legal series (Robak in Black , etc.) with mixed results. After leaving a Chicago hospital with untreatable stomach cancer, Charlie Cannert heads to Florida to find his missing wife, Martha, who went there to look for a place to retire. From his time as a “tunnel rat” in Vietnam to his vigilante crusades against molesters of children and the elderly, Charlie has led a life full of violence. Martha, meanwhile, has wound up after a vicious assault as a “Jane Doe” in a Florida state mental hospital. Still suffering from partial amnesia, Martha later escapes from the hospital and goes in search of Charlie, who by now is helping Florida cop Tom Ryan bring down his wife’s attackers. While the author vividly depicts the depressing world of elderly retirees preyed on by con men and murderers, some stiff dialogue and the slackening of narrative tension near the end undercut the strong premise. Fans will be saddened to learn that Hensley died at age 81 in August 2007. (Feb.)